As a technology for determining a sequence of introducing in-process items in a manufacturing stage into a manufacturing device, there is a technology for calculating a priority by a critical ratio (CR) method (see, for example, Patent Literature 1).
In the CR method, a value (CR value) is obtained by dividing a time remaining to complete the in-process items by a time remaining to complete a shipping of the in-process items so as to prioritize the in-process items of a product for which the time remaining to complete a shipping is the shortest.